Image processing apparatus and method for determining whether an original contains a specified image

ABSTRACT

An image processing apparatus and method includes a scanner for scanning an original and generating electrical image data representing an image of the original to be processed, a processor for processing the electrical image data supplied by the scanner, and a device for determining whether the original represented by the electrical image data contains a specified image based on the electrical image data supplied by the scanner. The scanner scans the original a plurality of times and the device performs its determination operation on the same original a plurality of times, once for each scanning operation.

This application is a division of application Ser. No. 08/181,068, filedJan. 14, 1994, U.S. Pat. No. 5,434,649, which is a division ofapplication Ser. No. 08/032,210, U.S. Pat. 5,321,470, filed Mar. 15,1993, now U.S. Pat. 5,321,470 which in turn is a continuation ofapplication Ser. No. 07/351,165, filed May 12, 1989, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus forprocessing an input image and recording the image on a recording medium,and more particularly to an image processing apparatus which is suitablyapplied to a color copying apparatus that is capable of effecting thecolor copying of an image of an original.

2. Related Background Art

Conventionally, an image processing apparatus is adapted to read animage of an original placed on an original table or the like and effecta faithful recording (copying) operation, as instructed by the operator.

The progress in copying technology in recent years, coupled with that incolor-image recording technology, has made it possible to output a copyimage which is very close to an image of an original.

Accordingly, with a conventional apparatus, if money or a certificatesuch as a negotiable instrument the copying of which is prohibited isplaced on the original table and copying is effected by misusing theapparatus or by way of a "prank" or the like, copying is effected asinstructed by the operator. Accordingly, there is the possibility ofreadily inducing an act of forgery, thereby presenting a major socialproblem.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide an imageprocessing apparatus which is capable of preventing in advance an act offorgery of money, a negotiable instrument, or the like, therebyovercoming the above-described problem of the conventional art.

To this end, in accordance with the present invention, there is providedan image processing apparatus comprising: means for determining whetheror not an original to be copied is an original having a specificpattern; and means for controlling an output of copying on the basis ofan output of the determining means. For instance, if the original to becopies is a banknote or an negotiable instrument, detection is carriedout to that effect and image processing is controlled.

Another object of the present invention is to provide an imageprocessing apparatus which effects suitable processing not only when animage utterly identical with a predetermined image but also an imagesimilar to the specified image are input, thereby preventing forgery.

According to this aspect of the invention, there is provided an imageprocessing apparatus comprising: input means for inputting informationon an image; evaluating means for evaluating on the basis of a specifiedstandard to what extent an input image is similar to a predeterminedimage; and conversion processing means for providing predeterminedconversion processing to the input information on an image incorrespondence with the evaluation of the evaluating means. Thus, areproduced image is modified in accordance with whether it is an imageof a bill or a stock.

Still another object of the present invention is to provide an imageprocessing apparatus which is capable of improving the accuracy of adetermination as to whether or not an input image is a predeterminedimage, and of minimizing the frequency at which faults occur due tomistaken determinations.

A further object of the present invention is to provide a novel copyingapparatus which has not heretofore existed.

It is another object of the present invention to provide an imageprocessing apparatus and method for increasing the reliability withwhich a forgery of an original image can be determined.

The present invention achieves this objective by providing an imageprocessing apparatus comprising scanning means, processing means anddetermining means. The scanning means scans an original and generateselectrical image data representing an image of the original to beprocessed. The processing means processes the electrical image datasupplied by the scanning means. The determining means determines whetheror not the original represented by the electrical image data contains aspecified image based on the electrical image data supplied by thescanning means. The scanning means scans the original image a pluralityof times and the determining means performs its determination operationon the same original a plurality of times in response to scanning theoriginal by the scanning means.

According to another aspect, the present invention which achieves theseobjectives relates to an image processing method comprising the steps ofscanning an original and generating electrical image data representingan image of the original to be processed, processing the electricalimage data supplied, and determining whether or not the originalrepresented by the electrical image data contains a specified imagebased on the electrical image data supplied. The scanning step iscarried out on the same original a plurality of times and thedetermining step is effected on the same original a plurality of times,once for each scanning.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription of the invention when read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a copying apparatus in accordance with afirst embodiment of the present invention;

FIG. 2 is a schematic side elevational view illustrating an example ofthe arrangement of image reading means shown in FIG. 1;

FIG. 3 is a schematic side elevational view illustrating an example ofthe arrangement of image outputting means;

FIG. 4 is a flowchart illustrating an example of a control procedure inaccordance with the first embodiment;

FIG. 5 is a schematic diagram of an essential part of means forprohibiting a copying output in accordance with a second embodiment;

FIG. 6 is a flowchart illustrating an example of a control procedure inaccordance with a third embodiment of the present invention;

FIG. 7 is a diagram of an image processing apparatus in accordance witha fourth embodiment of the present invention;

FIG. 8 is a block diagram illustrating an example of the arrangement ofa control unit provided in a reader unit thereof;

FIGS. 9A, 9B, and 9C are timing charts illustrating the operation of thecontrol unit;

FIG. 10 is a block diagram illustrating an example of the arrangement ofa bill-stock recognizing circuit;

FIG. 11 is a flowchart illustrating an example of an image changeprocessing procedure on the basis of the result of recognition.

FIG. 12 is a block diagram illustrating the arrangement of a bill-stockrecognizing circuit in accordance with a fifth embodiment;

FIG. 13 is a diagram illustrating the form of image change on the basisof the arrangement shown in FIG. 12;

FIG. 14 is a block diagram illustrating an example of the arrangement ofa bill-stock recognizing circuit in accordance with a sixth embodiment;

FIG. 15 is a diagram illustrating the form of image change on the basisof the arrangement shown in FIG. 14;

FIG. 16 is a flowchart illustrating an example of an image changeprocessing procedure on the basis of the result of recognition inaccordance with a seventh embodiment;

FIG. 17 is a block diagram illustrating an example of the arrangement ofa bill-stock recognizing circuit in accordance with an eighthembodiment;

FIG. 18 is a diagram illustrating the form of image change on the basisof the result of recognition in accordance with a seventh embodiment;

FIG. 19 is a block diagram illustrating the arrangement of a bill stockrecognizing circuit in accordance with a ninth embodiment;

FIG. 20 is a diagram illustrating the form of image change on the basisof the arrangement shown in FIG. 19;

FIG. 21 is a diagram illustrating an image processing apparatus inaccordance with a tenth embodiment of the invention;

FIG. 22 is a block diagram illustrating an example of the arrangement ofa video conversion circuit shown in FIG. 21;

FIG. 23 is a block diagram illustrating another example of thearrangement of the video conversion circuit shown in FIG. 21.

FIG. 24 is a diagram illustrating an image processing apparatus inaccordance with an eleventh embodiment of the invention;

FIG. 25 is a block diagram illustrating an example of the arrangement ofthe video conversion circuit shown in FIG. 24;

FIG. 26 is a block diagram illustrating a circuit configuration inaccordance with a twelfth embodiment;

FIG. 27 is a block diagram illustrating the configuration of arecognition circuit shown in FIG. 26; and

FIG. 28 is a top plan view illustrating a state at the time of readingand scanning an input original.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the accompanying drawings, a detailed description willbe given of the preferred embodiments of the present invention.

FIG. 1 illustrates a first embodiment of an image processing apparatusin accordance with the present invention.

In FIG. 1, the image processing apparatus comprises the followingcomponent parts: a central arithmetic processing unit 1 in the form of amicrocomputer; a ROM 2 in which an operation program and the like forthe CPU 1, which will be described later with reference to FIG. 4, arestored; a RAM 3 used for registration or the like in a process ofcontrol by the CPU 1; a keyboard 4 having a known group of input keys,such as a key for commanding copy start and a key for setting the numberof copies to be made; a keyboard interface circuit 5 for connecting thekeyboard 4 to a system bus 10; image reading means 6 for reading animage depicted on a set original; an image memory 7 for storing imagedata which has been read; and image outputting means 8 for outputtingthe stored image data; bill detecting means 9 for detecting whether ornot image data of a certificate the copying of which is prohibited, suchas money (hereinafter referred to as a bill) or a negotiable instrument(hereinafter referred to as a stock), is present in the image memory;and an image data bus 11 for transmitting the image data between therespective parts 6-9 at high speed.

FIG. 2 illustrates an example of the arrangement of the image readingmeans. In this drawing, an original illuminating lamp 61 is adapted toilluminate the surface of the original, a zoom lens 62 is adapted toform an image of the original on a CCD serving as a reading element, aCCD 63 is adapted to convert an image into an electrical signal, and anoriginal table 64 is composed of a transparent plate. Reference numerals65, 66, and 67 denote mirrors.

In FIG. 2, the original illuminating lamp 61 and the mirror 65 scan anoriginal 69 placed on the original table 64 with a surface thereof to beread facing downward. The light reflected from the surface of theoriginal is introduced into the zoom lens 62 via the group of mirrors,and an image is then formed on the CCD 63 so as to be converted into anelectrical signal.

FIG. 3 illustrates an example of the arrangement of the image outputmeans 8.

In FIG. 3, reference characters 81Y, 81M, 81C, and 81K respectivelydenote a primary charger for yellow, a primary charger for magenta, aprimary charger for cyan, and a primary charger for black. It should benoted that the accompanying letters Y, M, C, and K hereinafter similarlyindicate that the components having denoted by these characters are foryellow, magenta, cyan, and black, respectively.

An LED array 82 is turned on and off in response to image data, and adeveloping device 83 is adapted to apply a developer (toner or the like)of a corresponding color. Numeral 84 denotes a transfer charger; 85, acleaner; and 86, a photosensitive drum.

A pickup roller 87 is adapted to pick up a recording medium (hereinafterreferred to as copy paper) 810 accommodated in a paper feeding cassette811 by separating sheets of the copy paper one by one. Pairs of conveyorrollers 812-815 are provided in a passage for conveying the copy paper.A conveyor belt 816 is adapted to discharge recorded copy paper; fixingrollers 88 are provided in the vicinity of a discharge outlet; and adischarged paper tray 89 is used to stack discharged copy paper thereon.

FIG. 4 illustrates an example of a control procedure in accordance withthis embodiment, and the operation of the above-described arrangementwill be described with reference to this drawing.

First, if a power switch (not shown) is turned on, the CPU 1 executes apredetermined initializing routine (Step S1), and is set on standby forreceiving a command from the keyboard 4 after the temperature of thefixing rollers 88 reaches a predetermined level (Step S3).

When the operator instructs a copying operation by using the keyboard 1,the CPU 1 drives the image reading means 6 to read out an image of theoriginal (Step S5). The reading of this image is effected four times bychanging over a color filter, and is developed in the image memory 7 foreach color (yellow, magenta, cyan and black).

Subsequently, the bill detecting means 9 is operated, and adetermination is made as to whether or not the image data on the imagememory 7 is that of a bill or a stock certificate (Step S7). In thisembodiment, for instance, if the address of a readable area of theoriginal table 64 corresponds to that of a storage area on the imagememory 7, the determination can be effected by recognizing the size ofthe original on the basis of the size of a data development area on theimage memory 7 and by comparing its result with the sizes of bills andthe like stored in advance in the ROM 2 and the like. In addition, thisdetermination can also be effected by comparing the distribution ofcolor spectra of the original with data registered in advance.

If the size of the original corresponds to the size of a bill or thelike, the bill detecting means 9 outputs "1", and, if not, it outputs"0". If this output is "0" (Step 59), the CPU 1 outputs the image on theimage memory 7 as a color image by means of the image output means 8(Step S11). On the other hand, if the output is "1", the CPU 1 prohibitsthe outputting of an image (Step S13).

In the image outputting processing (Step S11), image formation iscarried out on the basis of a known electrostatic process. In otherwords, after the photosensitive drum 86 is charged with the primarycharger 81, the LED array 82 is turned on and off in correspondence withthe image data in synchronism with the rotation of the photosensitivedrum 86, thereby forming an electrostatic latent image. Thiselectrostatic latent image is developed by the developing device 83 bymeans of a developer (toner or the like) and is transferred by thetransfer charger 84 onto the copy paper 810 fed by the pickup roller 87.The output of a color image is realized by effecting the above-describedprocess for each of yellow, magenta, cyan and black. Upon completion ofdevelopment of the specified colors, the copy paper 810 is conveyed tothe fixing rollers 88 by means of the conveyor belt 816 so as to effectthermal fixing and is then discharged onto the discharged paper tray 89.

On the other hand, in the processing in Step S13, the CPU 1 does notstart the image output means 8, so that copying is prohibited and anoutput is not delivered. In other words, if the original is a bill orthe like, the outputting of an image is prohibited. In addition, anarrangement may be provided such that display of a predetermined errormessage or an alarm using speech is provided in connection with thisprocessing.

In order to ensure that the outputting of an image of the bill or thelike is thus ultimately prohibited, in addition to prohibiting theoperation of the image output means 8 as described above, theprohibition may be carried out before then. For instance, the scanningof the surface of the original is conducted four times, i.e., for eachcolor, and if the feature of the original, such as the size of theoriginal, becomes clear in that process, subsequent reading may beprohibited at that point of time, thereby prohibiting the outputting ofan image.

In addition, an arrangement may be alternatively provided such that theoutputting is prohibited after the copying operation by the imageoutputting means 8.

As described above in detail, in accordance with this embodiment, if adetermination is made that the image is a specified one, the outputtingof the image is prohibited, so that it is possible to prevent theforgery of a bill or the like.

FIG. 5 illustrates a second embodiment of the present invention forprohibiting the outputting after a copying operation. In thisembodiment, the copy paper on which image formation is carried out onceis not delivered to the outside, but is internally disposed of bycutting or the like.

FIG. 5 schematically illustrates an arrangement of an essential part ofthis embodiment. In this embodiment, regardless of the type of original,the process proceeds to the transfer of image onto the copy paper shownin FIG. 4. Then, if the output of the image detecting means 9 is "0",the conveyor belt 816 is set in the position indicated by the solid linein FIG. 5, and the copy paper 810 is conveyed by the conveyor belt 816to the fixing rollers 88 where and the copy paper 810 is subjected tothermal fixing and then discharged onto the discharged-paper tray 89.Meanwhile, if the output of the image detecting means 9 is "1", i.e., ifthe original was a bill or the like, the conveyor belt 816 is set in theposition indicated by the broken line in FIG. 5. Then, the copy paper810 which has been fed passes through a guide 100 and is conveyed to acutter 101 where it is disposed of by being cut into fine pieces, makingit impossible to obtain an output of copying.

Accordingly, in accordance with this embodiment, before a reproducedimage for forging is delivered outside the apparatus, the copy paper isdisposed of, thereby making it possible to prevent the forging of a billor the like.

In the foregoing embodiments, as a means of controlling the output ofcopying, the operation of the image output means 8 is prohibited, or thedischarge thereof is prohibited. However, an arrangement may be providedsuch that the operation of the image output means 8 itself is controlledin such a manner that the copy of a bill or the like will be unusable.

FIG. 6 illustrates an example of a control procedure in accordance witha third embodiment of the present invention for making a copy of a billor the like unusable.

In this embodiment, processing by means of Steps S23 and S25 is providedinstead of Step S13 in FIG. 4.

In other words, if the bill detecting means 9 detects a bill, a stock orthe like and outputs "1", the CPU 1 calculates a logical sum of imagesof yellow, magenta and cyan and an image of black, and converts theimages of yellow, magenta and cyan to that of black (Step S23). Then,the CPU 1 outputs an image by the image output means 8 as amonochromatic image (Step S25). Thus, by outputting a monochromaticimage, it becomes impossible for the operator who attempts to engage ina forging act to engage in the act by simply using a copying apparatus.

Although, in this embodiment, it is assumed that copying in black iseffected as an output of a monochromatic image, it is also possible toeffect monochromatic copying in yellow, magenta or cyan. Morespecifically, control of the image output means 8 in any form ispossible insofar as it is ensured that at least a faithful full-colorcopy is not produced. In addition, if, when a bill or the like isdetected before completion of the reading scanning described above,copying is effected with the contents stored in the memory 7 up untilthen, full-color copying will not be effected, so that this procedure isequally effective.

Although, in the foregoing embodiments, detection as to whether or notthe original being copied is a bill or the like is conducted on thebasis of a document size, it goes without saying that such detection maybe effected by using any form of means.

For instance, means used in automatic vending machines and the like forreading a magnetic pattern of a part or the whole of a bill may beprovided so as to compare that pattern with a pattern stored in advance.In this case, it is possible to provide an arrangement in which amagnetic head is provided in the original cover provided on the originaltable 64 for covering the original 69. Alternatively, in the case of acopying apparatus having an automatic delivery feeder (ADF) fororiginals, it is possible to adopt an arrangement in which a magnetichead is provided in its conveying passage.

In addition, it is also possible to adopt an arrangement in which a partor the whole of the image pattern of a bill or the like is read, and theread pattern is compared with a pattern which has been stored inadvance. As for this reading, in the case of an apparatus having theconfiguration of a digital copier such as the one described above, thereading operation of the image reading means 6 may be used as it is. Inthe case of the other types of apparatus, the reading head may beprovided on the original cover or conveying passage of an ADF or thelike. Alternatively, the illumination means may be provided on theoriginal cover, and a comparison may be effected by reading a watermarkpattern.

The present invention can be applied irrespective of the form of theimage output means 8. For instance, although an arrangement is adoptedin which an LED array is used in the above-described embodiments so asto form an electrostatic latent image on the photosensitive drum, anarrangement may be alternatively adopted in which a laser beam or thelike is used. Furthermore, the means of forming an electrostatic latentimage on the photosensitive drum is not confined to suchelectrophotographic type, but various other types may be used.

As described above, in accordance with the third embodiment of thepresent invention, if an attempt is made to copy an object the copyingof which is prohibited, such as a bill or a stock, detection of thatfact is carried out, and an output of copying is controlledappropriately, making it impossible for the operator to effect thedesired faithful but illegal copying. Thus, there is an advantage inthat the act of forgery can be prevented.

Particularly in this embodiment, the color original is output by beingconverted into a monochrome image, it is possible to ascertain what theoriginal image was like. In other words, when the operator's purpose incopying the stock is not forgery but, for instance, to preserve as adocument, that object can be attained.

FIG. 7 illustrates an example of a schematic internal structure of adigital color image processing system in accordance with a fourthembodiment of the invention. As illustrated in the drawing, this systemcomprises a digital color image reading unit (hereinafter referred to asa color reader) 401 provided in an upper portion thereof, and a digitalcolor image printing unit (hereinafter referred to as a color printer)provided in a lower portion thereof. This color reader 401 is adapted toread the color image information of an original for each color by meansof color separating means, which will be described later, and aphotoelectric conversion element such as a CCD, and to convert the sameinto electrical digital image signals. The color printer 402 is a laserbeam color printer for effecting recording by reproducing a color imagefor each color in response to those digital image signals and bytransferring them onto the recording medium a plurality of times in theform of digital dots.

First, an outline of the color reader 401 will be described. An originalis designated at 403, and platen glass 404 is for placing the originalthereon. A rod lens array 405 is adapted to condense a reflected imagefrom the original subjected to exposure scanning and to input the imageinto an equal-magnification-type full color sensor 406, components 405,406, 407 and 410 effecting exposure scanning in the direction of thearrow A1 integrally as an original scanning unit 411. Color-separatedimage signals read for each line during the exposure scanning areamplified to a predetermined voltage by a sensor output signalamplifying circuit 407, and are then input to a video processing unit412, which will be described later, by means of a signal line 501 so asto be subjected to signal processing. A detailed description of thisarrangement will be given later. It should be noted that the signal line501 is made into a coaxial cable so as to ensure faithful transmissionof signals.

A signal line 502 is for supplying a drive pulse for driving the equalmagnification-type full color sensor 406, and all the necessary drivepulses are generated in the video processing unit 412. A white plate 408and a black plate 409 are used for correcting the white level of videosignals and for correcting the black level thereof. If the white plate408 and the black plate 409 are illuminated with a halogen exposure lamp410, signal levels of the predetermined densities are respectivelyobtained and can be used for correcting the white level and the blacklevel of the video signals.

A control unit 413 incorporating a microcomputer carries out all of thefollowing control of the color reader 401: display at an operating panel420 via a bus 508; control of key input via digitizer 416, control ofthe video processing unit, and control of a bill-stock-featureextracting circuit 452; detection by position sensors S1, S2 of theposition of the original scanning unit 411 via signal lines 509, 510;control via a signal line 503 of a stepping motor drive circuit 415 foreffecting the pulse driving of a stepping motor 414 via line 506 formoving the scanning unit 411 by means of pulleys 417 and cables 418; theON/OFF control of the halogen exposure lamp 410 by an exposure lampdriver 421 via a signal line 504; control of the amount of light; andcontrol of digitizer 416 via a signal line 505, an internal key, and adisplay unit, etc.

A color image signal read by the aforementioned exposure scanning unit411 during the exposure scanning of the original is input to the videoprocessing unit 412 from the amplification circuit 407 via the signalline 501. The color image signal is then provided with various types ofprocessing to be described later inside the video processing unit 412,and is transmitted to the color printer 402 via an interface circuit 456(communication between video processing unit 412 and printer 402 iscarried out via signals 511 to 516).

A description will now be given of an outline of the color printer 402.A scanner is designated at 711 and has a laser output portion forconverting a video signal from the color reader 401 into an opticalsignal (received at PWM circuit 778 in housing 700), a polygonal mirror712 having the shape of a polyhedron (e.g., octahedron), a motor forrotating this mirror 712, an f/θ lens (image-forming lens) 713, etc. Areflection mirror 714 is adapted to change the optical path of a laserbeam, and a photosensitive drum is designated at 715. A laser beam madeemergent from a laser output portion is reflected by the polygonalmirror 712, is transmitted through the lens 713 and the mirror 714, andis made to linearly scan (raster scan) the surface of the photosensitivedrum 715, thereby forming a latent image corresponding to the image ofthe original.

In addition, reference numeral 717 denotes a primary charger; 718, awhole image exposure lamp; 723, a cleaner section for recoveringresidual toner which was not transferred; and 724, a pre-transfercharger, all of these components being provided around thephotosensitive drum 715.

A developing unit 726 is adapted to develop an electrostatic latentimage formed on the surface of the photosensitive drum 715 by the laserexposure. Development sleeves 731Y, 731M, 731C, 731Bk directly effectdevelopment in contact with the photosensitive drum 715. Toner hoppers730Y, 730M, 730C, 730Bk are designed to retain reserve toner. Screws 732are adapted to transfer the developer. These sleeves 731Y-731Bk, tonerhoppers 730Y-730Bk, and screws 732 constitute the developing unit 726,and these components are disposed around a rotary shaft P of thedeveloping unit 726. When, for instance, a toner image of yellow isformed, the yellow toner development is carried out at the positionshown in the drawing. At the time of forming a toner image of magenta,the developing unit 726 is rotated with the shaft P as a center, and thedevelopment sleeve 731M within a magenta developing unit is disposed atthe position at which it is brought into contact with the photosensitivedrum 715. The development in cyan and black is also effected in asimilar manner.

In addition, a transfer drum 716 is designed to transfer a toner imageformed on the photosensitive drum 715 onto the copy paper 791. Anactuator plate 719 is adapted to detect the moving position of thetransfer drum 716. A home position sensor 721 is adapted to detect themovement of the transfer drum 716 to a home position as the transferdrum 716 is brought into proximity with this actuator plate 719.Reference numeral 725 denotes a transfer drum cleaner; 728, ade-electrificator; and 729, a transfer charger. These members 719, 720,725, 729 are disposed around the transfer drum 716.

Meanwhile, paper feeding cassettes 735, 736 are used for accommodatingcopy paper serving as a recording medium. Paper feeding rollers 737, 738are adapted to feed copy paper from the cassettes 735, 736. Timingrollers 739, 740, 741 are adapted to time the paper feeding andconveyance. The paper fed and conveyed via these components isintroduced into a paper guide 490, is wound around the transfer drum 716with its leading edge held by a gripper, and is then moved by rotationof drum 716 to an image transfer location.

A drum rotating motor 550 is adapted to synchronously rotate thephotosensitive drum 715 and the transfer drum 716. A releasing claw 750is adapted to remove the paper from the transfer drum 716 aftercompletion of the image forming process. A conveyor belt 742 is adaptedto convey the removed paper. An image fixing unit 743 fixes the paperwhich has been conveyed by the conveyor belt 742 and has a pair of heatpressure rollers 744, 745 (other conventional elements 746 to 748 arealso shown).

A printer controller to control the various parts of the printer 402 hasa PWM circuit 778 for effecting pulse width modulation of the imageinformation transferred from the reader 401 and then supplying the sameto the scanner 711.

Referring now to FIG. 8, a detailed description will be given of thecontrol unit 413 of the reader 401 in accordance with the presentinvention.

(Control Unit)

The control unit 413 comprises a CPU 422 in the form of a microcomputerand organically effects control of video signal processing, as well ascontrol of the lamp driver 421 (via I/O port 426) for exposure andscanning, the stepping motor driver 415, the digitizer 416, and theoperating panel 420 via the signal lines 508 (bus), 504, 503, 505, etc.,respectively, in correspondence of the contents stored in a program ROM423, a RAM 424, and a RAM 425. Incidentally, as for the RAM 425, it isassumed that non-volatility is assured by a battery 431. A signal line505 is for serial communication which is generally used, and theoperator inputs necessary data on the basis of a protocol between theCPU 422 and the digitizer 416. Namely, the signal line 505 is one forinputting data for editing the original, such as coordinates at the timeof movement, synthesis, and the like, designation of an area,designation of a copy mode, designation of a magnification, etc. Thesignal line 503 is one whereby the CPU 422 gives commands on thescanning speed, distance, forward movement, backward movement, etc., tothe motor driver 415. Upon receipt of a command from the CPU 422, themotor driver 415 outputs predetermined pulses to the stepping motor 414,thereby rotating the motor 414. Serial interfaces (I/Fs) 429, 430 aregenerally used, e.g., ones which are realized by LSIs for serial I/Fssuch as 8251 by Intel Corporation. The digitizer 416 and the motordriver 415 are provided with similar circuits (not shown).

In addition, sensors S1, S2 are used to detect the position of theoriginal exposure scanning unit (designated at 411 in FIG. 7), S1representing the home position in which the white level correction ofimage signals is effected. The sensor S2 detects the fact that theoriginal exposure scanning unit is located at the tip of the image, andthis position serves as a reference position of the original.

(Printer Interface)

Signals ITOP, BD, VCLK, VIDEO, HSYNC, SRCOM (511-516) are respectivelyinterface signals between the color printer 402 and the reader 401 shownin FIG. 7. All the video signals VIDEO 514 read by the reader 401 aretransmitted to the color printer 402 on the basis of the aforementionedsignals. ITOP 511 is a synchronous signal in the image feeding direction(hereinafter referred to as the subscanning direction). This synchronoussignal is produced once for each transmission of the four colors(yellow, magenta, cyan, and black), i.e., a total of four times on eachsuch occasion. This signal is made synchronous with the rotation of thetransfer drum 716 and the photosensitive drum 715 so as to be alignedwith the image at the tip of the original when the toner image istransferred onto the copy paper wound around the transfer drum 716 ofthe color printer 402, at a point of contact with the photosensitivedrum 715. This signal 511 is transmitted to the video processing unitdisposed in the reader 401 and is output as an interruption of the CPU422 in the controller 413 (via interruption controller 427).

The CPU 422 controls images in the subscanning direction for editing orthe like by using ITOP interruption as a reference. BD 512 is asynchronous signal in the raster scanning direction (hereinafterreferred to as the main scanning direction) which is produced onceduring one rotation of the polygonal mirror 712, i.e., once during oneraster scanning. The image signals read by the reader 401 aretransmitted to the printer 402 one line at a time in the main scanningdirection in synchronism with the signal BD 512. VCLK 513 is asynchronous clock for transmitting the digital VIDEO signal 514 of 8bits to the color printer 402, and allows the VIDEO signal 514 to besent via flip-flops 332, 335 (shown with buffer amplifiers 333, 334,336, 337), as shown in FIG. 9B.

HSYNC 515 is a synchronous signal in the main scanning direction whichis produced in synchronism with VCLK 513, and has the same period as thesignal BD 512. Strictly speaking, the VIDEO signal 514 is transmitted insynchronism with HSYNC 515. This arrangement is adopted because, sincethe signal BD 512, which is produced in synchronism with the rotation ofthe polygonal mirror 712, contains in large amounts the jitter of themotor for rotating the polygonal mirror 712, if the VIDEO signal 514 issynchronized with the BD signal as it is, jitter would occur in theimage, so that HSYNC 515 is required which is produced in synchronismwith jitter-free VCLK on the basis of the BD signal.

SRCOM is a signal line for semi-double bilateral serial communication.As shown in FIG. 9C, a command CM is transmitted in synchronism with an8-bit serial clock SCLK during the transmission of a synchronous signalCBUSY (command busy) sent from the reader. In response, a status signalST is returned in synchronism with an 8-bit serial clock occurringduring the transmission of SBUSY (status busy) sent from the printer.All the exchanges of information including commands from the reader tothe printer, such as the color mode and the selection of a cassette,information on the status of the printer, such as jamming, papershortage, wait, etc., are conducted via this communication line SRCOM.

FIG. 9A shows a timing chart for transmitting one four-color(full-color) image on the basis of ITOP and HSYNC. ITOP 511 is producedonce during one rotation or two rotations of the transfer drum 716. At atiming 1, data of a yellow image is transmitted from the reader 401 tothe printer 402. Similarly, data of a magenta image is transmitted at atiming 2, that of a cyan image at a timing 3, and that of a black imageat a timing 4. Thus, a full-color image is formed on the copy paper withfour colors superposed thereon. If, for instance, the image density inthe feeding direction is assumed to be 16 pel/mm with respect to 420 mmin the longitudinal direction of an A3-size image HSYNC is transmitted420×16=6,720 times. At the same time, this signal is output to a clockinput for a timer circuit 428 provided in the controller circuit 413,which is adapted to supply an interruption HINT 517 to the CPU 422 afterthe lapse of a predetermined count. Thus, the CPU 422 effects imagecontrol in the feeding direction, such as withdrawal and movement.

(Bill-Stock-Feature Extracting Circuit)

Referring now to FIG. 10, a description will be given of the operationof a bill-stock-feature extracting circuit 452.

FIG. 10 is a block diagram illustrating an example of the configurationof the video processing unit 412 including the bill-stock-featureextracting circuit 452. The color image signal read by the exposurescanning unit 411 shown in FIG. 7 is input from an amplification circuit407 to the video processing unit 412 via the signal line 501. In thisvideo processing unit 412, that input is received by a video receivercircuit 460, and the misregistration of each color and shading arecorrected by a video preprocessing circuit 461 so as to output r, g, bsignals.

The preprocessed video signal is input to the bill-stock-featureextracting circuit 452, and after being converted from a luminancesignal into a density signal by a LOG conversion circuit 462, the signalis subjected to masking and under-color removal (UCR) by a masking/UCRcircuit 463. Then, the signal is transmitted to the color printer 402via the following: an italic image/mirror image processing circuit 464,a color balance circuit 465, a color conversion circuit 466, amagnification conversion circuit 467, a texture processing circuit 468,an edge emphasis smoothing circuit 469, a video signal synthesizationcircuit 470, and a video driver circuit 471, and then via a signal lineVIDEO 8.

The processing circuits provided in the video processing unit 412 areconnected to each other via an internal bus VUBUS and are furtherconnected to the CPU 422 via a CPU bus transceiver 472 and a signal line508.

In the bill-stock-feature extracting circuit 452, on the basis of the r,g, b signals that are input into it, a determination is made as towhether or not the input data matches with the features of apredetermined bill or stock, and a determining result thereof isreturned to the CPU 422 via the VUBUS.

On the basis of a determining result with respect to a number offeatures, the CPU 422 makes a final determination as to whether or notthe original being examined is a bill or stock. If the answer is YES,the CPU 422 sets a conversion parameter for a specific processingcircuit via the VUBUS, the parameter being such that it will not allow afaithful image of the original to be reproduced.

As for the processing of a determination on the matching effected by thebill-stock-feature extracting circuit 452, the determination may be madewith respect to the input signals r, g, and b by making a comparisonwith data on the distribution of color spectra of the originalregistered in advance in a ROM or the like, or by comparing a pattern ofa part or the whole of the image of the original with pattern dataregistered in advance, or effecting such processings in combination. Inaddition to the extraction of features with respect to the contents ofthe image data that has been read, it is possible to provide otherappropriate processing such as addition of a circuit or the like fordetermining the size, magnetic pattern, watermark pattern or the like ofthe original and to transmit such data to the CPU 422.

FIG. 11 shows an example of parameter changing processing which iscarried out by the CPU 422 on the basis of a determination on a numberof features obtained from the above-described feature extracting circuit452. This procedure can be stored in the ROM 423.

First, in Step S101, various results of determination are input from theaforementioned circuit 452 and others. Then, a final determination ismade on the basis of the input results as to whether or not the originalbeing examined is a bill or a stock (Step 5103). In accordance with thatcalculated result, a changing parameter is set in the processing circuit463 and the like in Step S105.

A description will now be given of examples of implementing the detailsof parameter changing.

The following formulas (a) to (d) are examples of changing the colorwhen a determination is made that the original being examined is a billor a stock, and this processing is carried out by changing theparameters of masking and UCR with respect to the masking/UCR processingcircuit 463. ##EQU1##

Formula (a) is an example of usual masking, whereas, if the matrix[m_(ij) ] is changed into that shown in formula (b), the color changestotally from that of the original, so that the recorded image cannot beused as a circulatable one as a bill or a stock. However, the contentsof the stock can be recorded.

In addition, formula (c) is an example in which the image is printed ina specified color, while formula (d) is an example in which the image isprinted in black.

As described above, in accordance with this embodiment, even in the casewhere it is determined that the original is a bill or a stock, it ispossible to produce a copy although it is not faithful to the original,but sufficient to ascertain the contents described therein. Thus, it ispossible to preserve the contents of the stock as a record.

FIG. 12 illustrates a fifth embodiment of the present invention. In thedrawing, reference numeral 450-2 denotes a bill-stock determiningcircuit, and in this example a CPU is provided so as to effect controlin correspondence with the determination of a bill or the like. Alogarithmic circuit 462 transforms the output of circuit 450-2 beforeproviding the latter to masking circuit 463.

A signal 480 is adapted to control a color which is output to themasking/UCR processing circuit. The other functions are identical tothose shown in FIG. 10.

In the case where a usual copying operation is carried out, as shown at(a) in FIG. 13, the masking/UCR processing circuit 463 is controlled insuch a manner that VIDEO 8 is changed over in the order of yellow,magenta, cyan, and black in synchronism with the iTOP signal output fromthe printer 402. When it is determined in the bill-stock determiningcircuit 450-2 that the original is a bill or a stock, the color of theprinted image is changed by changing the order of the changing over ofthe colors, as shown at (b) in FIG. 13.

Thus, since the masking/UCR processing circuit is controlled directlyfrom the bill-stock determining circuit 450-2, it is possible to effectprocessing for changing the color independently of the CPU 422, so thatthe program of the CPU 422 does not become complicated, and, even if theprogram of the CPU 422 is altered, the prevention of forgery can beeffected more positively.

FIG. 14 illustrates a sixth embodiment of the present invention.

In the drawing, a bus changeover signal 481 is adapted to control a bustransceiver 472 for the CPU bus 508, and a bill-stock determiningcircuit 450-3 operates independently of the CPU 422, constantlymonitoring the video signals r, g, b. If a determination is made thatthe original is a bill or a stock, the CPU bus transceiver 472 is closedto exclusively use the VUBUS, and if, for instance, a specific parameteris written in the italic image/mirror image processing circuit 464, itis possible to print an italic image, as shown at (a) in FIG. 15.

If such a conversion is carried out forcedly, a printed image which canbe distinguished clearly from an authentic one is output, thereby makingit possible to prevent forgery.

FIGS. 15 (b)-(c) are other examples in which mirror images are output bycontrolling the italic image/mirror image processing circuit 464, inwhich (c) is an example in which an output is delivered in reduced formby controlling the magnification processing circuit 467, (d) is anexample in which an output is delivered by through lateral longitudinalindependent magnification by controlling the magnification processingcircuit 467, and (e) is an example in which an output is delivered byadding on the characters "copy" by controlling the video signalsynthesization circuit 470 and a character-pattern generator 473.

In addition, the color balance may be changed substantially bycontrolling the color balance processing circuit 465. Alternatively, animage may be output in a specific color (monochrome) by controlling thecolor conversion circuit 466, or a monotone image may be output bycontrolling the color conversion circuit 466. Furthermore, an image maybe output in the form of mosaic texture by controlling the textureprocessing circuit 468, or fine lines may be deleted through filtering,or blurring processing may be effected by controlling the edge emphasissmoothing processing circuit 469. Moreover, an image may be output bybeing subjected to negative-positive conversion by controlling the LOGconversion circuit 462.

Since the arrangement is provided such that processing for forgeryprevention is carried out in the video processing unit 412, it ispossible to assure forgery prevention more positively.

FIG. 16 is a diagram illustrating a seventh embodiment of the presentinvention.

In this embodiment, in the feature extracting circuit 452, the CPU 422calculates the degree of the "likelihood of being a bill or a stock",and sets a conversion parameter for a specific processing circuit incorrespondence with the degree of the "likelihood of being a bill or astock".

Since the processing of a matching determination carried out by thefeature extracting circuit 452 is identical with that shown in FIG. 7, adescription thereof will be omitted.

Specifically, FIG. 16 illustrates an example of a parameter conversionprocessing procedure carried out by the CPU 422 on the basis of a numberof evaluations obtained from the above-described feature extractingcircuit 452. This procedure can be stored in the ROM 423.

First, in Step S111, various evaluations (determining results) are inputfrom the aforementioned circuit 452 and others. Then, in Step S113, anappropriate calculation is performed on the basis of the evaluations,and a determination is made on the degree or extent of the "likelihoodof being a bill or a stock certificate " (the evaluations constitute anarray which may be simply a collection of numbers used in actualcomputations, or the array may be used to address the contents of alook-up table in ROM 423, and this array is sometimes hereinafter termeda "non-binary-number" to indicate that it could be anything ranging froma collection of several numbers, to a single value chosen on a(non-binary) scale, to an array of several different types of values).In Step S115, conversion parameters are determined in correspondencewith that calculated result, and are set in the processing circuit 463or the like. Not only the aforementioned degree or extent evaluationsbut also the conversion parameters can be formatted in advance as tablesin the ROM 423.

A description will now be given of an example of the contents ofparameters to be converted.

The following formulae (e) and (f) are examples in which the color ischanged in correspondence with the degree of the likelihood of being abill or a stock certificate, and this processing is effected by changingmasking/UCR parameters for the masking/UCR processing circuit 463.##EQU2##

Formula (e) is an example of usual masking, and if matrix [m_(ij) ] ischanged into that shown in formula (f), the color is output by beingconverted in correspondence of the value of a which is determined by thedegree of the likelihood of the original being a bill or a stock.Consequently, when a is large, the reproduced color changes totally fromthat of the original, so that the reproduced copy cannot be used as acirculatable one as a bill or a stock. However, the contents (number orthe like) given in the stock can be preserved as a record. Meanwhile,with respect to an original image whose degree of likelihood of being abill or a stock is low, the change in color is suppressed to a smalllevel by making a small. It goes without saying that other methods maybe used as the method of changing the color.

As described above, in accordance with the seventh embodiment of thepresent invention, since the image conversion is effected incorrespondence with the degree of the likelihood of the original being abill or a stock, it is possible to form an image having a certain degreeof picture quality even with respect to an original for which adetermination is difficult. Hence, the amount of copies for which adetermination of an "erroneous copy" is made can be reduced.

FIG. 17 illustrates an eighth embodiment of the present invention.

In the drawing, a bill-stock determining circuit is designated at 450-2,and in this embodiment, the arrangement is such that a CPU is providedto effect control in correspondence with the degree of the "likelihoodof the original being a bill or a stock certificate". A signal line 488is adapted to control the degree of an italic image with respect to theitalic image/mirror image processing circuit 464.

In conversion into an italic image, the configuration of the image isdeformed as shown in FIG. 18. By virtue of the processing by the circuit450-2, control can be effected via a signal 488 in such that manner thatθ is set increasingly close to 0° from 90° in correspondence with thedegree of the likelihood of the original being a bill or a stock.

Thus, in this embodiment, since the italic image/mirror image processingcircuit 464 is controlled directly by the bill-stock determining circuit450-2 to a degree corresponding to the degree of the likelihood of theoriginal being a bill or a stock certificate, forgery-preventingprocessing can be effected independently of the CPU 422. Hence, theprogram of the CPU 422 does not become complicated, and it makes itstill more difficult for the would-be forger to obviate theforgery-preventing processing.

FIG. 19 illustrates a ninth embodiment of the present invention.

In the drawing, a bus changeover signal 481 is adapted to control a bustransceiver 472 with respect to the CPU bus 508, and a bill-stockdetermining circuit 450-5 constantly monitors the video signals r, g, bby operating independently of the CPU 422. If it is determined that theoriginal is likely a bill or a stock, the CPU bus transceiver 472 isclosed, and to exclusively use the VUBUS is used. Then, for instance, ifspecific parameters are written in the italic image/mirror imageprocessing circuit 464, it is possible to print an italic image, asshown in FIG. 18.

Since such a conversion is effected to a degree corresponding to thedegree of the likelihood of original being a bill or a stock, when adetermination is made that the original is obviously a bill or a stock(when the degree of likelihood is large), a printed image which can beclearly distinguished from an authentic one is output, thereby making itpossible to prevent forgery. On the other hand, if the determination isnot clear-cut (the degree of probability is small, the conversion iseffected at a small degree, with the result that the possibility ofimparting unexpected trouble to the operator is small.

FIGS. 20(a)-(c) illustrates other examples in which the outputprocessing corresponding to the degree is effected forcedly.

FIG. 20(a) is an example in which the image is output by being reducedin correspondence with the degree of the likelihood of the originalbeing a bill or a stock by controlling the magnification processingcircuit 467. In addition, FIG. 20 (b) is also an example in which animage is output by being subjected to lateral longitudinal independentmagnification in correspondence with the degree of the likelihood of theoriginal being a bill or a stock. Furthermore, FIG. 20(c) is an examplein which an image is output with the characters "copy" added on with asize or density corresponding to the degree of the likelihood of being abill or a stock by controlling the video signal synthesization circuit470 and the character-pattern generator 473.

In addition, the color balance may be changed by controlling the colorbalance processing circuit 465, or an image may be output with a mosaictexture corresponding to the degree of its likelihood by controlling thetexture processing circuit. Alternatively, an image may be output afterbeing subjected to blurring processing through filtering incorrespondence with the detected degree of likelihood by controlling theedge emphasis smoothing processing circuit 469.

Since the arrangement is provided such that processing for forgeryprevention is carried out in the video processing unit 412, it ispossible to assure the forgery prevention more positively.

FIG. 21 illustrates an arrangement in which a forgery preventing deviceis provided on the printer 402 side in accordance with a tenthembodiment of the present invention.

In the drawing, a bill-stock determining circuit 450-4 is provided in aprinter controller 700, and monitors the video signals that are inputsequentially thereinto. Upon determining that the original is a bill ora stock in the same way as described above, the bill-stock determiningcircuit 450-4 controls the video conversion circuit 451. Then, a printedimage is changed substantially from the original by providingappropriate processing, such as by thinning out the image, making thelines smaller or larger, using half-tone dots, and adding on characters.

FIG. 22 illustrates an example of the video conversion circuit 451 whichis adapted to effect thinning out based on result 482 of thedetermination as to the identity of the document. In the drawing,reference numeral 901 denotes a selector, while 902 denotes an AND gate.Numeral 903 denotes a J-K flip-flop, which effects thinning out for eachpicture element selected.

FIG. 23 is an example of a video conversion circuit 451' for makinglines smaller (or larger). In the drawing, numerals 910, 911 and 913denote D-type flip-flops, while 912 denotes a selector. Numeral 914denotes a comparator, and if an arrangement is provided such that asmall (or larger) value is selected by the selector 912, it is possibleto make the lines smaller (or larger) in the main scanning direction.

With respect to half-tone processing, an example of a processing circuitis not illustrated, but an arrangement may be provided such that a finepattern of a bill or the like is made to form a moire by subjecting avideo image to fine-dot processing.

As described above, in accordance with this embodiment, since a forgerypreventing device is incorporated on the printer side, it is possible toeffectively prevent forgery even in a case where an image is read by areader which is not provided with a forgery preventing device.

It should be noted that the circuit for determining a bill or a stock isnot confined to those of the above-described embodiments, and it goeswithout saying that any circuit which achieves the desired results maybe used for the same. In addition, as for the printer as well, not onlythe electrophotographic type of the above-described embodiments but alsovarious other types may be used.

FIG. 24 illustrates an example in which a forgery preventing device isprovided on the printer 402 side in accordance with an eleventhembodiment of the present invention.

In the drawing, a bill-stock determining circuit provided in the printercontroller 700 is denoted by 450-6, and monitors video signals that areinput sequentially thereinto. Upon determining that the original is abill or a stock in the same way as described above, the bill-stockdetermining circuit 450-6 controls the video conversion circuit 451, incorrespondence with the aforementioned degree of "likelihood". Then, aprinted image is changed substantially from the original as appropriateprocessing is provided in correspondence with the degree, such as bythinning out the image, making the lines smaller or larger, usinghalf-tone dots, and adding on characters.

FIG. 25 illustrates an example of the video conversion circuit 451 whichis adapted to effect thinning out based on result 482 of thedetermination as to the identity of the document. In the drawing,reference numeral 1001 denotes a selector, while 1002 denotes an ANDgate. An n-dividing counter 1003 outputs "1" once for each n-number ofpicture elements, and the elector 1001 selects 0 instead of the signalsonce for each n-number of picture elements via the AND gate 1002,thereby performing the thinning-out operation.

As described above, in accordance with this embodiment, since a forgerypreventing device is incorporated on the printer side, it is possible toeffectively prevent forgery even in a case where an image is read by areader which is not provided with a forgery preventing device.

It should be noted that the circuit for determining a bill or a stock isnot confined to those of the above-described embodiments, and it goeswithout saying that any circuit which can provide the desired result maybe used for the same. In addition, as for the printer as well, not onlythe electrophotographic type of the above-described embodiments but alsovarious other types may be used.

FIG. 26 illustrates a circuit diagram of a twelfth embodiment of thepresent invention which is applied to a color image reproducingapparatus using a laser beam printer.

In the drawing, a color original 2101 to be duplicated is placed on anoriginal mounting glass table 2102. A light source 2103 is adapted toilluminate the original 2101, while a converging rod lens array 2104(e.g., Selfock (tradename) lens array) which forms on a CCD line sensor2105 an image of the light (an image of the original) reflected from theoriginal illuminated by the light source 2103. The CCD line sensor 2105is arranged such that filters of red (R), green (G), and blue (B) areapplied on the line alternately, and converts the image of the originalinto electrical signals by separating it into the three primary colors.The aforementioned components 2103-2105 are integrally accommodated in areading head (carriage) and is made to effect scanning by a scanningmechanism (not shown) in the direction of the arrow (subscanningdirection) shown in the drawing, thereby scanning and reading the imagedepicted on the original 2101.

In addition, a sample hold circuit 2106 sample holds analog electricalsignals (video signals) sent from the line sensor 2105 and converts theminto time series signals of R, G, B. An A/D (analog-digital) converter2107 subjects output signals from this sample hold circuit 2106 toanalog-digital conversion. A shading correction circuit 2108 correctsvariations in the sensitivity for one CCD line of the CCD line sensor2105 and unevenness in illumination. A logarithm conversion circuit 2109converts the R, G, and B signals corrected by the shading correctioncircuit 2108 into complementary-color density signals of cyan (C),magenta (M), and yellow (Y). Reference numeral 2110 denotes an inkingcircuit for generating ink (K, black) signals by extracting the minimumvalue among the C, M, and Y signals output from the logarithm conversioncircuit 2109 and also denotes a UCR circuit for subtracting from the Y,M, and C signals a component corresponding to the K signal. A maskingcircuit 2111 corrects unnecessary absorption and the like of anoutput-side coloring material. A selector circuit 2112 selects signalsto be sent to the printer (a laser beam printer in this embodiment) fromamong the Y, M, C, and K signals obtained as described above.

In addition, a gate circuit 2113 turns on and off outputs sent from theselector 2112 to the printer in response to control signals from a CPU(central arithmetic processing unit) 2128. A D/A (digital/analog)converter 2124 converts digital signals sent from the reader via thegate circuit 2113 into analog signals. A comparator 2116 compares theoutput of the D/A converter 2114 with a triangle wave signal of apredetermined period produced from a triangle wave generator 2115,obtaining a pulse width modulation (PWM) signal having a pulse widthproportional to the image signal. This PWM signal is applied to asemiconductor laser 2118 via a laser driver 2117.

The light beam issued by the semiconductor laser 2118 is modulated bythat PWM signal and reaches a rotating photosensitive drum 2121 (see thebroken line in the drawing) via a polygonal mirror 2119 rotating at highspeed and a reflecting mirror 2120.

An electrostatic latent image formed on the photosensitive drum 2121upon application of the laser beam is developed by a rotary developingdevice 2122 sequentially in the order of C, M, Y, and K, and is recordedas toner images of the respective colors. This toner image istransferred onto copy paper 2124 on the transfer drum 2123 sequentiallyin the order of C, M, Y, and K. The copy paper 2124 is conveyed from apaper cassette (not shown) and is wound around the transfer drum 2123.Upon completion of the transfer of C, M, Y, and K images on fouroccasions, the printed copy paper proceeds through the positionindicated at 2125 is subjected to thermal fixing by a fixer 2126, and isdischarged to the outside as a final reproduced image.

A determining circuit 2127 determines whether or not the pattern on theoriginal 2101 is a specified pattern, and is controlled by the CPU 2128.

In the above-described arrangement, four executions of scanning andreading are necessary with respect to the original 2101 in synchronismwith the C, M, Y, and K outputs of the printer, and the selector 2112changes over the output signals and sends to the printer signalscorresponding to C, M, Y, or K. In this embodiment, therefore, thearrangement is such that the determining circuit 2127 is operated by adifferent algorithm in correspondence with a plurality of times of theoriginal scanning operation, and its determining results are evaluatedin a comprehensive manner, thereby improving the accuracy with which aspecific pattern is determined.

Referring now to FIG. 27, a detailed description will be given of theoperation of the above-described determining circuit 2127. FIG. 27illustrates a detailed internal circuit configuration of the determiningcircuit 2127. The R, G, and B signals from the shading correctioncircuit 2108 shown in FIG. 26 are respectively subjected to binaryprocessing by comparators 2201-2203 in the light of predeterminedthreshold values from threshold value store 2204. An AND circuit 2205calculates a logical product of the results of this binary processing,and outputs "1" only to the picture element which exceeds the thresholdvalue with respect to all of R, G, and B.

An edge point detection circuit 2206 detects an edge point of the imageof the original, and, when, as shown in FIG. 28, a bill 2302, i.e., theoriginal 2101, is placed on the original-mounting glass table 2102, thiscircuit 2206 detects an edge point on one side of the bill 2302 (a pointon a straight line 2303). An angle detection circuit 2207 detects arotating angle θ (see FIG. 28) of the bill 2302 on the basis of theresult of detection by the edge point detection circuit 2206. An affineconversion circuit 2208 cuts off a part (e.g., a hatched portionindicated at 2304 in FIG. 28) of an input image of the original on thebasis of the detection result θ of the angle detection circuit 2207 andeffects rotation by (-θ) so as to be written in a memory 2209.

By virtue of the above-described arrangement, an image is written in amemory 2209 in the state in which the cut-out portion 2304 is notrotated. Meanwhile, a normal image pattern corresponding to theaforementioned cut-out portion 2304 is written in a memory 2210 from theCPU 2128. Then, the contents of the memory 2209 and the contents of thememory 2210 are superposed on each other in a matching circuit 2211, anda value of their correlation is determined. The value of correlationdetermined by the matching circuit 2211 is output again to the CPU 2128,where, on the basis of the value of correlation, a determination is madeas to whether or not the input image coincides with a normal imagepattern (hereinafter referred to as the normal pattern.

In the above-described operation, there is clearly an uncertainty of±180° in angle detection in the angle detection circuit 2207, so that asingle calculation of matching does not lead to a proper determinationwith respect to an image inverted by 180°. For this reason, in thisembodiment, if an upright proper pattern is written in the memory 2210in the first scanning of the original, while an inverted (180° inverted)proper pattern is written therein in the second scanning of theoriginal, the 180° uncertainly can be overcome in two scanning anddetermining operations. Namely, in FIG. 26, the first scanning anddetermination are made to correspond to the outputting of a cyan image,while the second scanning and determination are made to correspond tothe outputting of a magenta image, and if a determination is made on thebasis of either of the two determining results that the input imagecoincides with the proper pattern, the the CPU 2128 immediately turnsoff the gate circuit 2113, cutting off an output of the image signal tothe printer. By virtue of this arrangement, since at least the yellowimage and the black image are not written onto the photosensitive drum2121, the duplicated image outputted to the copy paper can be clearlydiscriminated from the input original, making it possible to suit thepurpose of forgery prevention.

Referring now to FIG. 27, a description will be given of a modificationof this embodiment. In this modification, the above-describeduncertainty concerning 180° can be overcome at one time by the provisionof two systems of the circuit having a configuration such as the oneshown in FIG. 27. Furthermore, the reading density is changed for thefirst scanning and the second scanning. Namely, during the first readingscanning, an image thinned out for each other picture element in theaffine conversion circuit 2208 is written in the memory 2209, while,during the second reading scanning, the image is not thinned out and iswritten in the memory 2209 as it is with the density which has beenread. Proper patterns corresponding to respective densities are writtenin advance in the memory 2210. By virtue of this arrangement, even incases where it is impossible to obtain a value of sufficient correlationduring the first matching, if a value of high correlation can beobtained during the second matching, the CPU 2128 can determine that theinput image has coincided with the proper pattern.

As the other embodiments, the following various types are conceivablyadopted:

Threshold values supplied to the comparators 2201 and the 2203 shown inFIG. 27 are varied during the first and second scannings.

An image to be written in the memory 2209 shown in FIG. 27 is shifted bythe portion of a number of picture elements during the first and secondscannings, thereby absorbing the misregistration between the inputpattern and the proper pattern.

The proper pattern to be written in the memory 2210 shown in FIG. 27 isvaried during the first and second scannings. For instance, the patternof a ten thousand yen note is used during the first scanning, while thepattern is changed to the pattern of a thousand yen note during thesecond scanning.

In the foregoing embodiment, it goes without saying that the number ofscannings is not restricted to two. In addition, the the number ofscannings is not restricted to four times or less. For instance, thefollowing processing is possible: If a determination is made during fouror less scannings that the input image is close to a proper pattern,determination processing is continued by carrying out only the originalscanning without discharging the copy paper from the transfer drum 2123,and the fifth transfer is effected when the input image coincides withthe proper pattern, whereupon the overall surface of the duplicated copyis inked out.

A description will now be given of another modification of the twelfthembodiment of the present invention.

In this modification, an image is not output during the determiningprocess of the first scanning, and if it is determined in this processthat the original is close to a proper pattern of a bill or the like,scanning is stopped at that point of time. When it is not determinedthat the original is close to the proper pattern, four readings ofimages corresponding to C, M, Y, and K are continuously made and outputsof video signals are delivered to the printer, outputting a duplicatedimage.

When the scanning is suspended, a message is output from the CPU 2128 toa liquid crystal display 2130 or the like to the effect that theoperator should rearrange the original or take other appropriate step,thereby prompting a restart. When a restart is designated by theoperator through a key 2131, the determining and duplication processingsuch as those described above are restarted.

By virtue of this arrangement, it is possible to overcome faults indetermination caused by a slight mispositioning of the original, angularerrors thereof, etc.

The above-described method of determining a specific image byabstracting a specific pattern can be applied to all of theabove-described embodiments.

As described above, in accordance with the twelfth embodiment of thepresent invention, the operation of effecting a determination byextracting a specific pattern from an image of the original is repeateda plurality of times, and the results of the repeated determinations areevaluated in a comprehensive manner, a final determination is made as towhether or not a specific pattern is included in the image of theoriginal. Hence, it is possible to obtain the following advantages: Theaccuracy with which the determination is made is improved substantially,and the forgery preventing function of the color image copying apparatusis enhanced. At the same time, the possibility of hindering normalcopying operations can be reduced to a remarkable degree.

The present invention is not restricted to the above-describedembodiments, and various other modifications are possible withoutdeparting from the spirit of the invention which is solely defined inthe appended claims.

What is claimed is:
 1. An image processing apparatus comprising:scanningmeans for scanning an original and generating electrical image datarepresenting an image of the original to be processed; processing meansfor processing the electrical image data supplied by said scanningmeans; and determining means for determining whether or not the originalrepresented by the electrical image data contains a specified image,based on the electrical image data supplied by said scanning means,wherein said scanning means scans the same original a plurality of timesand said determining means performs its determination operation on thesame original a plurality of times in response to scanning the originalby said scanning means.
 2. An apparatus according to claim 1, whereinsaid processing means and said determining means are commonly suppliedwith the electrical image data by said scanning means.
 3. An apparatusaccording to claim 1, wherein said scanning means includes a sensor forsupplying data representing a plurality of colors.
 4. An apparatusaccording to claim 1, further comprising controlling means forprohibiting or changing image reproduction by said processing means whensaid determining means determines that the original represented by theelectrical image data contains the specified image.
 5. An apparatusaccording to claim 4, wherein said controlling means is capable ofinhibiting image output.
 6. An apparatus according to claim 4, whereinsaid controlling means is capable of inhibiting said scanning meansafter initiation of the scanning sequence.
 7. An apparatus according toclaim 4, wherein said controlling means is capable of inhibiting theoutput of said scanning means.
 8. An apparatus according to claim 4,wherein said controlling means is capable of changing the electricalimage data output from said processing means.
 9. An apparatus accordingto claim 4, wherein said controlling means are provided to effect, at aplurality of timings, scanning of the original by said scanning means,and for allowing said determining means to effect repeatedly adetermining operation each such scanning.
 10. An apparatus according toclaim 9, wherein said controlling means changes a reading density of ascanning operation of said scanning means during a first and a secondscanning.
 11. An apparatus according to claim 4, wherein saidcontrolling means is capable of actuating a means for disposing of anillegal copy produced by said processing means.
 12. An apparatusaccording to claim 4, wherein said controlling means effects a change ofa reproduction image.
 13. An apparatus according to claim 1, whereinsaid processing means includes a laser beam printer.
 14. An imageprocessing method comprising the steps of:scanning an original andgenerating electrical image data representing an image of the originalto be processed; processing the electrical image data supplied; anddetermining whether or not the original represented by the electricalimage data contains a specified image based on the electrical image datasupplied, wherein said scanning step is carried out on the same originala plurality of times and said determining step is effected on the sameoriginal a plurality of times, once for each scanning.